The Anhydrobiotic Potential of the Terrestrial Nematodes Plectus parietinus and Plectus velox.

Within the taxon Nematoda, many species possess an anhydrobiotic potential similar to other microscopic animals, such as tardigrades and rotifers. This interesting capability enables them to survive conditions even of extreme dehydration. We examined the anhydrobiotic abilities of the two widespread terrestrial nematode species, Plectus parietinus and P. velox, by subjecting adult and juvenile life stages of both species to two different desiccation regimes, one with a short time of adaption (2 hr) and the other with a long time of adaption (48 hr) prior to complete desiccation and recorded the nematodes' recovery after 24 hr of rehydration. We found adults of P. parietinus to be the superior anhydrobiotes compared to adults of P. velox at short times of adaption, whereas at a long time of adaption this pattern was reversed. Moreover, our results showed that a long time of adaption significantly increased the recovery rate, independent of species or life stage. Additionally, we found adults to have a remarkable higher anhydrobiotic potential than juveniles, presumably due to a larger amount of resources in adult nematodes or due to a different morphology (cuticle, surface area to volume ratio). Plectus parietinus as well as P. velox showed a distinct anhydrobiotic potential although there were obvious differences between those two species, probably ascribable to different species-specific anhydrobiotic mechanisms and rates of water loss.